1. Field of the Invention
The present invention relates to a light shield sheet, an optical apparatus, and a method of manufacturing a light shield sheet. Particularly, the present invention relates to a light shield sheet used for a camera, an optical apparatus, and a method of manufacturing a light shield sheet.
2. Description of Related Art
With rapid spread of digital cameras and mobile phones with digital camera functions, optical components used for these optical apparatus are on the improvement. One of important techniques for the optical apparatus is to eliminate unwanted incident light to prevent flare or ghost from occurring in an image.
The flare is a phenomenon where a bright part appears in an image, which is likely to occur by strong incident light entering a lens, such as when a camera faces a light source. The ghost is a phenomenon where an object image is formed in a different position from the right position due to multiple reflection of incident light or the like.
In order to avoid flare and ghost, various components have been researched and developed, including a lens-barrel and a lens stop. For example, Japanese Unexamined Patent Publication No. 2003-270506 describes a technique that places a light shield member with a stopper at its end inside a lens-barrel so as to prevent ghost from occurring.
Though these techniques considerably reduce ghost and flare, complete prevention has not been achieved. For example, since the light shield sheet used for a lens stop has a certain thickness, incident light is reflected on its side face to cause ghost or flare. However, this thickness is necessary in terms of essential light shielding effect, mechanical strength, shape stability, reliability in environments, handling ability in assembling, and so on.
The present invention has been accomplished to solve the above problems and an object of the invention is thus to provide a light shield sheet having a necessary thickness and capable of preventing ghost and flare from occurring, an optical apparatus, and a method of manufacturing a light shield sheet.